Acquired Immune Deficiency Syndrome (“AIDS”) is one of the most deadly diseases to affect human. This disease cripples a person's immune system, leaving the person susceptible to opportunistic infections, malignancies, or other pathological conditions against which a normal immune system would have protected the person. After one develops symptoms of AIDS, death generally occurs within 2-3 years of diagnosis. The etiology of AIDS and related disorders has been identified as being associated with infection by a class of lymphotrophic retrovirus termed human immunodeficiency virus (HIV), which is spread when body fluids, such as semen, vaginal fluids, or blood, from an infected individual are passed to another individual. Believed to have originated in Africa, HIV infection or AIDS is now a global epidemic. In the U.S. alone, there are an estimated over one million people who have been infected with HIV.
Because of the devastating effect of AIDS and the increasing spread of HIV infection around the world, much effort has been devoted to elucidate the mechanism of how HIV attacks the human immune system and identify new approaches for preventing HIV infection. It is now understood that two glycosylated HIV envelope proteins, gp120 and gp41, mediate the attachment of virions to cell surface receptor molecules (such as CD4), initiating the process of internalization of HIV into the cells. Because the binding of gp120 and CD4 is one crucial step in HIV infection of CD4+ cells, many studies have focused on various strategies that block the gp120-CD4 binding.
On the other hand, it has been recognized that the predominant routine of HIV transmission is via sexual contact. Thus, there exists a need for new prophylactic methods that can effectively prevent HIV infection upon initial contact. This invention addresses this and other related needs.